This invention relates to a connector terminal, and more particularly to a connector terminal for connecting large electrical currents.
In a commonly-used connector, a male terminal is inserted into a female terminal, thereby forming an electrical connection. In this case, particularly in the type of connector for dealing with a larger current, a highly reliable connection between the two terminals is required. Therefore, a construction shown in FIG. 7 is adopted. This figure shows one of many pairs of mating terminals provided in female and male connector housings that are to be fitted together.
The female terminal 20 shown in FIG. 7 has an insertion tubular portion 21 at its front portion, and the male terminal 22 has a shaft portion 23, which can be inserted into the insertion tubular portion 21. In this case, the outer diameter of the shaft portion 23 is slightly larger than a bore diameter of the insertion tubular portion 21; and the shaft portion 23 is divided along an axial direction by an expanding slot 24 extending along a longitudinal axis thereof. With this arrangement, by forcibly deforming the entire shaft portion 23 radially inward, the shaft portion 23 can be inserted into the tubular portion 21. Accordingly, when the male terminal 22 and the female terminal 20 are connected, an adequate contact pressure can be achieved due to a resilient restoring force of the shaft portion 23 of the male terminal 22.
However, the following problems have been encountered with the above connector construction. First, in the above construction, a large contact resistance is maintained over a time period starting with the insertion of the terminal 22 into the terminal 20 until completion of the insertion operation. Therefore, the insertion operation is difficult, in particular, because the larger an allowable current is, the larger the size of the terminals become, and therefore a larger insertion force is needed to construct the connector.
Furthermore, when the insertion and withdrawal of the terminal are repeated, or when the terminals remain in an inserted position for a long period of time, the resilient restoring force of the male terminal 22 may be decreased, and as a result, the contact pressure is decreased. In addition, when the terminals are in a withdrawn position, the outer diameter of a front end of the shaft portion 23 is larger than the bore diameter of the insertion tubular portion 21, and therefore the insertion at an initial stage is difficult.